David Willcocks conducts a rehearsal in 2001.
Photograph: Jim Bovin/AP

For many radio and television audiences around the world, the Festival of Nine Lessons and Carols broadcast from King’s College, Cambridge, is the sound of Christmas, and it was the choir’s director, David Willcocks, who turned this Victorian invention into a landmark in the musical year. But Willcocks, who has died aged 95, was behind many other performances, recordings and musical careers that are woven into the nation’s cultural fabric: a Fauré Requiem by which all others are judged, the introduction to British audiences of the Duruflé Requiem, a St Matthew Passion recorded in English, a whole armoury of descants that breathed new life into the hymnal, and a wave of new musicians who came through the Royal College of Music, London, during his decade as director there.

In the years before his appointment at King’s in 1957, Willcocks started honing a method of choir training quite new for its time, but that would later become highly influential, especially to the Oxbridge-nurtured “authentic” choirs. He inflected music with a light, rhythmic pulse, he insisted on exact tuning, and he encouraged explosive consonants that themselves aided the rhythmic punctuation. He had a deep loathing for “flat” singing, insisting, sometimes almost pathologically, on the highest, brightest, major thirds.

The release in 1967 of the Fauré Requiem, then little known in Britain, with the baritone John Carol Case and, in the Pie Jesu, the treble Robert Chilcott, now a renowned composer of choral music, attracted an audience for this transcendent work far beyond the normal confines of the church.

The Festival of Nine Lessons and Carols was introduced at King’s in 1918, and first broadcast in 1928. By the time of Willcocks’s departure in 1973, it had become an international institution, and, widely admired for his combination of gentlemanly charm, scholarship and pinpoint musicianship, he went on to act as an adviser to the wider musical establishment.

David Willcocks’ arrangement of The Sussex Carol, sung in the 2011 Festival of Nine Lessons and Carols at King’s College Chapel

He had succeeded Reginald Jacques as conductor of the Bach Choir in 1960, transforming an unwieldy, overweight sound into a remarkably nimble chorus, despite its 300 voices, that toured in Britain and overseas. While dominated by the music of JS Bach, the choir’s repertoire grew to include newer work, including Honegger’s King David and Janáček’s Glagolitic Mass. Britten’s War Requiem was performed in several countries for the first time under Willcocks, who also prepared the choir for the 1963 recording with the London Symphony Orchestra, conducted by the composer. It won a Grammy. And while today’s taste is often for Bach sung and played by smaller forces, annual performances of the St Matthew Passion are remembered for their overwhelming power; his recording of it was made in 1978.

He became director of the Royal College in 1974, and was knighted in 1977. Throughout this period he was also general music editor at Oxford University Press. He broke new ground here, too: from the four volumes of Carols for Choirs that he had produced from 1961 onwards, he selected, with the composer John Rutter, 100 Carols for Choirs (1987). The carol book that was to outsell all others, it repackaged old carols and presented new ones, in a format that good amateur singers could master. Willcocks fostered the fashion for treble descants that could also be sung by amateurs as well as by trained voices, and which lit up the original material.

In 1981 he directed the music at the wedding in St Paul’s Cathedral of Prince Charles and Diana Spencer, and its worldwide viewership must have constituted the largest single audience he ever appeared before. Once more, new audiences opened up in consequence, with the soprano Kiri Te Kanawa singing Handel’s Let the Bright Seraphim. His fanfare to the national anthem manages to combine due dignity with welcome bravura.

David Willcocks’ arrangement of O Come, All Ye Faithful, sung in the 2009 Festival of Nine Lessons and Carols at King’s

Born in Newquay, Cornwall, to Theophilus, a Barclays Bank manager, and his wife Dorothy, David displayed such musical promise that he was sent as a boy to join the choir of Westminster Abbey for four years. Ernest Bullock was the organist at the time. An early sign of political awareness was shown when the master, playing a chord to the young Willcocks, asked him: “Do you hear the voice of God in that chord, my boy?” “Oh yes, sir,” came the immediate reply.

On leaving the abbey, he became a scholar at Clifton college. He had such facility in organ playing and in general musicianship that he next took what later seemed to be an inevitable step, winning an organ scholarship to King’s College, Cambridge, where the organist and choirmaster was Boris Ord.

After one year of study the war intervened and Willcocks served with immense distinction in the Duke of Cornwall’s Light Infantry in Normandy, attaining the rank of major at a young age. In 1944 he was awarded the Military Cross. With typical humility he was always rather coy about this honour, remarking that it was an accident that he had taken so many prisoners, that luck had led him through it all.

After the war he resumed his organ scholarship, and it may be assumed that it was at this time that he acquired the baffling art (stupefying at parties) of sitting cross-legged on the floor and playing jazz, his back to the piano, with hands crossed behind his head. He was a whippy man who was naturally gifted at sport. His lethal game of squash led many a cocky choral scholar to concede a whimpering defeat.

Willcocks then became a fellow of King’s (1947-50) and at the same time organist of Salisbury Cathedral. As choirmaster and organist at Worcester Cathedral (1950-57) he also conducted the Three Choirs Festival, until the call from King’s took him back to Cambridge, now as fellow and organist, the successor to Ord.

David Willcocks in discussion with his successors at King’s, Stephen Cleobury and Philip Ledger

He was a man of immense energy and organisation. He had been known to fly from the US for a Bach Choir rehearsal and return the next morning. His in-tray was always empty, each inquiry answered with respect and intelligence. He was tough but kind, an essentially loyal man with great sympathy and kindness, especially for those who clearly needed it.

He also influenced the music profession in another, less direct way. While at King’s there came under his tutelage (whether directly or indirectly) many immature but high talents. He noticed them, and helped them and advised entry into the world of professional music. This was radically new thinking for the time. Among those whom he advised and helped and who went on to become luminaries in the musical firmament were Simon Preston, Andrew Davis, Philip Ledger, and most of the original King’s Singers and some of their successors.

He is survived by his wife Rachel (nee Blyth), whom he married in 1947, two daughters and a son. Another son predeceased him.

•David Valentine Willcocks, organist, choirmaster and composer, born 30 December 1919; died 17 September 2015

• This article was amended on 18 September 2015. The original stated that Sir David Willcocks was a chorister under Henry Walford Davies. This has been corrected. It was further amended on 22 September 2015. Willcocks’s recording of the St Matthew Passion was not the first made in English: this had been done previously by the conductors Serge Koussevitzky, Reginald Jacques and Leonard Bernstein. The book 100 Carols for Choirs was not the first in a series, but a selection from four volumes of Carols for Choirs, the first of which, edited by Willcocks and Jacques, was published in 1961. Willcocks’s wife Rachel’s maiden name was not Gordon, but Blyth.